Help with a faulty PC, no video!

[XVB]

Hello all!

I have a PC that wont start at all, the fan and the front lights are on, but no video signal no even the BIOS POST, nothing. This computer has been repaired before but I have no clue what has been done to it. What are the following steps to determine the cause of the problem? could be BIOS? thanks in advance.

 

[AWS]

Give a little more info on the system and we might be able to help.

 

[XVB]

All I know is that it has been repaired before, so that takes away the monitor as a possible cause, I even tried two other monitors with no luck.

It makes no HD noises and no beeping at all, and I tried booting with the XP cd and the pc wont respond. As I said, there is no POST from BIOS, just starts the fan and the front panel lights normally. But it sends absolutely no signal to the monitor.